3 on the tree

[mikewarme]

Anybody done a conversion to auto ? Im looking at buying a 69 pickup with a 350 and 3 on the tree. Hate the idea of only 3 speeds. Bad milage on highway? Or whats the opionon? Good like that?

[71swb4x4]

A TH350 only has 3 gears. Are you looking to put in a 700r4 or comparable?

[mikewarme]

Yes that would be ideal. But which column should I use?

[oldgold70c10]

I just got done putting a 700r4 in my '70 burb. I used a auto column out of a 71-72 truck. All you got to do is adjust the linkage for the extra gear.

[capev86]

some of the vendors sell a revised gear indicator for doing an overdrive swap, otherwise i wouldn't even bother if just going to a turbo 350. manual trans already has no slip whereas an auto would need a lockup converter to get true 1:1 in third gear. plus you need all the other bits and a good radiator to handle the extra heat that an auto puts off, yadda yadda yadda...

my 72 burb has the 3 on the tree and i plan to keep it. i'm swapping to a 4.10 third member and have a 406sbc to go in. i like the nostalgia of this trans. i did put in a 4 row radiator to handle that bigger engine and for trailer towing duties and without an auto or a/c to put extra demand on cooling it will be an awesome setup. i eventually plan to upgrade my saginaw to a factory overdrive unit. i do have a spare 700r4 in good working shape (still hooked up to that 406) but i don't want to join the pack. the big engine under the hood with column shifted manual will really throw people a loop!

[Sublvr72]

I'm doing this swap right now. Went from a 307/3OTT and I'm going to a 454/TH400.

For the shifter I'm using a B&M Mega Shifter on the floor, I had one in the suburban and liked it so I'm doing it again...

[rsmarr1982]

Originally Posted by mikewarme

Anybody done a conversion to auto ? Im looking at buying a 69 pickup with a 350 and 3 on the tree. Hate the idea of only 3 speeds. Bad milage on highway? Or whats the opionon? Good like that?

you wanna sel all the 3 on the tree parts? i wanna make my 69 3 on the tree

[rsavage]

I had a truck 4 speed and went to a 200 4R. Used a auto column from a truck that had 3 speed auto. You will need an auto crossmember (you will have to remove your standard bellhousing mount crossmember, probably need a new starter that bolts to the block (if yours is a 3 bolt that bolts to the bell housing) a new flex plate, a radiator that has provisions for the trans cooler lines (or a separate aftermarket cooler), trans cooler lines ( the lines for a TH350 or 400 will work with a 200 4R if you go to an OD trans, you'll have to remove your clutch pedal and z bar, get the correct transmission yoke and shorten drive shaft if necessary, wire up the lock up converter (if you do an OD), possibly get a longer speedo cable and the correct speedometer driven gear, and get either an original auto linkage set up or an aftermarket rod with heim joints (I prefer) that costs about 30 bucks to connect the column to the transmission. If your back up light switch is on the 3 speed tranny, you'll have to hook up a combination neutral safety/backup light switch on the auto column.